1. Technical Field
This invention relates to the field of ballasting. More particularly, this invention relates to the field of wastewater ballasting.
2. Discussion
Vessels typically take on fuel, food, and water in-port in preparation for seagoing operations. During seagoing operations, the fuel, food, and water are consumed aboard the vessel. The consumption of fuel during seagoing operations requires the in-take of ballast to maintain the stability of the vessel. In addition, the consumption of food and water results in the generation of wastewater, e.g., graywater, blackwater, galley water, that must be stored aboard the vessel. The wastewater must be treated and disinfected before it can be discharged to the sea, or the wastewater must be discharged in-port at dedicated disposal facilities that are able to receive such toxic effluent. When the vessels return to port, the vessels take on additional fuel, food, and water in preparation for further seagoing operations. The in-take of additional fuel, food, and water during in-port operations requires the vessel to perform de-ballast operations to maintain the stability of the vessel.
In such known systems, vessels discharge seawater ballast from ballast tanks during in-port refueling and de-ballast operations. In such known ballast systems and methods, vessels intake and store seawater as ballast during seagoing operations. The vessels discharge this seawater ballast during in-port ballast operations to maintain the stability of the vessel as additional fuel, food, and water is loaded onto the vessel. The intake of seawater ballast from one region of the world and the subsequent discharge of that seawater ballast in another region of the world may contaminate marine sanctuaries, ecosystems, and other biologically-sensitive areas, particularly local or regional waters that surround port locations. This contamination occurs when the seawater ballast is discharged directly into local or regional waters, thereby introducing non-indigenous marine life and similar foreign pathogens and marine organisms that are present in the seawater ballast into local or regional waters.
To reduce such contamination, known systems may treat the seawater ballast with biocides and other toxins prior to discharge of the seawater ballast in local or regional waters. This treatment is designed to kill and remove the marine organisms that are contained in the seawater, so that such organisms do not contaminate local or regional waters during vessel ballast operations that utilize seawater ballast. In such known systems that rely on seawater to ballast the vessel, vessels must store untreated wastewater aboard the vessel in holding tanks and then pump the untreated wastewater ashore during in-port operations to disposal facilities that are qualified to receive such toxic effluent. Alternatively, they may discharge such effluent at sea, or if approved for Alaska, in port.